US President Donald Trump seems poised to declare a national emergency and redirect Pentagon resources towards building a wall on the border with Mexico, after his talks with congressional Democrats went nowhere.

Visiting the border in Texas on Thursday, Trump met with federal, state and local officials and repeated the need for a barrier along the border with Mexico.

“We need a wall – whether it’s steel or concrete, call it whatever you want – but we need it,” Trump argued in a video posted on Twitter, flanked by Border Patrol agents.

One way or another, we will get it done.

One possible way out of the impasse is for Trump to declare a national emergency and redirect some of the Pentagon funding to have the Army Corps of Engineers build the border barrier. It seemed likely that he would do so, based on his address to the nation on Tuesday, but in the end he decided to give the Democrats another chance to change their mind.

On Wednesday, however, Trump walked out of the talks with Senate Minority Leader Chuck Schumer (D-New York) and Speaker of the House Nancy Pelosi (D-California), after they ruled out any money for the wall, ever. Trump called the meeting a “total waste of time.”

Speaker Pelosi’s refusal to negotiate on Wall/Barrier funding – even if the government were to be reopened – virtually ends congressional path to fund Wall/Barrier.

Time for President @realDonaldTrump to use emergency powers to build Wall/Barrier.

Will he do it?

There are increasing indications that Trump is considering doing just that. Earlier in the day, he told reporters he had the “absolute right” to declare a national emergency, adding, “I haven’t done it yet. I may do it. If this doesn’t work out, probably I will do it. I would almost say definitely.”

By Thursday evening, NBC was reporting that Department of Defense officials had briefed the president on a possible plan of building the wall using the emergency declaration. Citing “three US officials familiar with the briefing” – anonymous, of course – NBC said the proposal would involve funds allocated to flood prevention and protection projects in California as well as money allocated to rebuild Puerto Rico after damage from Hurricane Maria.

The Army Corps of Engineers could build 315 miles (506 km) of the border barrier in about 18 months, NBC reported, citing the unnamed officials.

“The Department of Defense is reviewing available authorities and funding mechanisms to identify options to enable border barrier construction,” Navy Captain Bill Speaks, a Pentagon spokesman, told USA Today, adding that “it would be inappropriate to comment further on those efforts” as the emergency declaration has not been made.

Can he do it?

Even some of the president’s most outspoken critics have conceded he has the constitutional authority to invoke a national emergency, though Democrats have vowed to try and block it in both the Congress and the courts.

Overruling Trump’s emergency declaration would take veto-proof majorities in both the House of Representatives and the Senate, however, which the Democrats lack. As for seeking a court injunction, it is unclear who would have standing to file a claim – though it seems likely California would try if the NBC story about relief funds proves accurate.

There are currently 31 ongoing national emergencies declared by the US government, CNN reported, citing documents from the Congressional Research Service and the Federal Register. The oldest one dates back to 1979 and the Iranian revolution, while the most recent – dated November 27, 2018 – authorizes sanctions against certain individuals over the “situation in Nicaragua.”

Due to the impasse between Trump and the Democrats, a quarter of the US government has been shut down since December 22. The shutdown is affecting some 800,000 federal employees, who will miss their first paycheck on Friday.